Natasha Marie Harris (30) died on February 25, 2010, after a cardiac arrest, Invercargill/Southland Coroner David Crerar heard at yesterday's inquest in Invercargill.
There was also a lack of potassium in her blood, probably relating to excessive consumption of soft drink.
Her mother-in-law, Vivien Hodgkinson, told the Otago Daily Times after the inquest none of the family had known of the dangers because there were no warnings, but now "fizzy drink in general doesn't come into our house".
The family was hoping to gain compensation from Coca-Cola for the children, who were now in care.
"It's destroyed the whole family. There's eight little children aged under 12 and their dad had to sit down after school and tell them their mother was dead. It's been very traumatic for everyone."
A Coca-Cola Oceania representative, who was at the inquest as an observer, told the court the company did not believe there was any basis for finding the consumption of Coke caused Ms Harris' death.
"We deeply sympathise with the tragic death of Ms Harris, but we are firmly of the view her death was not due to the purchasing of Coca-Cola."
She said medical evidence referred to other contributing factors and the "possibility rather than a probability" of the role Coke played.
"She drank at least 10 litres a day. As a family, we would buy four 2.5 [sic] litres a day, the maximum on special. The Coke would be for Natasha to consume over the course of the day.
"The first thing she would do in the morning was have a drink of Coke and the last thing she would do in the day was have a drink of Coke by her bed," he said.
Mr Hodgkinson said he had known Ms Harris since she was 16. She had always drunk Coke, but in the last seven or eight years she had increased her habit from several 1.5-litre bottles up to five bottles a day.
Others confirmed Ms Harris would drink upwards of four litres of Coke a day and police said seven litres a day was a mid-range figure of her consumption.
Mr Hodgkinson said she was addicted to Coke and without it she would get moody, irritable, "quite nasty" and be low in energy. Yet he never suspected the beverage was making her ill.
"I never thought about it. It's just a soft drink, just like drinking water. I didn't think a soft drink was going to kill her."
Mr Hodgkinson told the court Ms Harris drank no other beverage and very little alcohol.
Since she had been unwell, she did not eat breakfast, ate only snacks at lunch and often went without dinner. All her teeth had been removed because they were rotting out, causing a dentist to remark about drinking too much Coke.
Mr Crerar put it to Mr Hodgkinson that he knew alcohol was bad for him.
"Do you know that not having a balanced diet is bad for you too?
" He replied: "Yeah, I suppose so. It's different being able to afford it with eight children. We ate what we could, when we could."
Mr Crerar also suggested that even if Coke bottles had warnings labels on them, Ms Harris may not have heeded the advice, given she was a smoker, and cigarette packets carried health warnings.
But Mr Hodgkinson believed she would have stopped her 30-cigarettes-a-day habit because she did not want to die and leave her children without a mother.
Medical evidence stated the main cause of death was from a cardiac arrhythmia.
Pathologist Dr Dan Mornin told the court Ms Harris had severe hypokalemia, a lack of potassium in the blood, probably relating to excessive consumption of soft drink.
He said although it was difficult to confirm this from postmortem tests, it was consistent with her symptoms of tiredness and lack of strength and with other cases of heavy soft drink consumers. It was likely her daily vomiting was due to too much caffeine, medically known as caffeine toxicity.
Dr Mornin said the combination of factors, including poor diet, probably played a role in her death.
Ms Hodgkinson told the court her daughter-in-law's consumption of Coke became "a family joke" because she was always seen with it. She would go "crazy" without Coke and would beg her to buy her some if she had been for too long without.
Mr Crerar reserved his decision.
- Written by Juliet Larkin.